Spray drying is a widely used process in the liquid process forming and drying industry for the production of powdered, granulated or massive solid products from solutions, emulsions, suspoemulsions and pumpable paste liquids. Therefore, spray drying is an ideal process when the particle size distribution, residual moisture content, bulk density and new granules of the finished product must meet the standards of jing.
By adopting the drying method, the gas-solid two-phase contact surface area in the spray dryer is large, and the drying time is short, generally 5 to 30 s, which is suitable for drying the heat sensitive material. The product obtained by drying has good performance, and particles of 30 to 50 mm can be obtained, and the product has good fluidity and fast solubility. The disadvantage is that the dryer has a large volume and a low heat transfer coefficient, resulting in low thermal efficiency and high power consumption.
There are many classification methods for spray dryers. According to the flow direction of gas and liquid, it can be divided into parallel flow, counter flow and mixed flow; according to the installation method of atomizer, it can be divided into upper spray type and lower spray type; The structure can be divided into centrifugal type, pressure type and air flow type; according to whether the heating gas is circulated, it can be divided into open type, partial circulation type and closed type.
The sticking phenomenon is a prominent problem that hinders the normal operation of the spray dryer, and the spray drying process of the solid preparation (especially the traditional Chinese medicine) is particularly obvious. The sticky wall of the material is not only unfavorable for the operation of the collection, but with the extension of time, the sensitive sticky wall material will deteriorate into a non-conforming material. From a process point of view, the solution includes selecting the right solvent, adding excipients, and changing the process parameters. However, there is not much room for adjustment of these methods, so a fundamental solution must be sought from the perspective of the equipment. Researchers have studied the problem of sticking and agglomeration in the drying process, and believe that the main cause of sticking is the wall temperature.
Spray dryer sticking walls generally have the following three conditions:
1. The semi-wet material sticks to the wall: the reason is that the sprayed droplets have already contacted the wall before they reach the surface drying, so they stick to the wall, and the position of the sticky wall is generally the droplets sprayed against the atomizer. On the plane of the motion trajectory, and the structure of the atomizer, the hot air is related to the motion state in the tower;
2. Hot-melt sticky wall of low-melting material: The reason is that the material reaches the melting point at a certain temperature and begins to melt and become sticky and adhere to the wall;
3, the surface adhesion of dry powder: dry powder in the limited space will always have some touch on the wall, this is unavoidable, but such a sticky wall is generally not thick, as long as the air is blown or gently tapped Can be shaken, zui simple solution is the inner wall polishing, can solve this problem to a certain extent.
Common methods for preventing sticking walls are as follows:
1. Use a wall-mounted drying tower with air cooling to keep the wall temperature below 50 °C;
2. Introducing a secondary air cooling tower wall through the tangential direction of the tower wall cyclone;
3. Install an air broom consisting of a row of nozzles near the wall of the tower and slowly rotate it along the tower wall;
4, the tower wall increases the air hammer, through the impact of the air hammer, forcibly make the sticky wall material detach;
5. Increase the processing precision of the equipment, and the inner wall polishing of the tower can also reduce the sticking wall.
Long Range LiDAR Radar
Long distance LiDAR sensor series are particularly easy to communication thanks to their fixed connector, which can be plugged it up and off by yourself. Voltage is wider from 8v before to 36v. Low power consumption feature makes it beceome a very competitive, high performance-price ratio, long range Laser Distance Sensor.
Highlights:
> Measurement frequency: 400 Hz (Max 60m 3000Hz)
> Long range: 200m
> High temperatures: -10~+50℃
> UART output
> Connector design: easy to use
Parameters:
Accuracy
|
±10cm(<50m) /±1%(>50m)*
|
Measuring Unit
|
cm
|
Measuring Range (without Reflection)
|
0.1-200m
|
Interface options
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Serial/usb/rs232/rs485/bluetooth
|
Measuring Frequency
|
400 Hz
|
Laser Class
|
Class I
|
Laser Type
|
905nm
|
Weight
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About 20g
|
VInput Voltage
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8V-36V
|
Resolution
|
1cm
|
Size
|
43*35*21mm
|
Operating Temperature
|
-15℃~50℃
|
Storage Temperature
|
-40℃~85℃
|
Chengdu JRT Main Ranging Modules: Industrial Laser Distance Sensors, Laser Rangefinder Sensor, Tof LiDAR Sensors.
Speed Laser Sensor,Long Range Lidar,Long Range 3D Lidar,Long Range Radar Sensor
Chengdu JRT Meter Technology Co., Ltd , https://www.accuracysensor.com